Autonomous navigation control system, autonomous navigation control method, autonomous navigation control program, mobile unit, and server

Abstract

The objective is to provide an autonomous navigation control system, an autonomous navigation control method, an autonomous navigation control program, a mobile body, and a server that can suppress a decrease in the continuity of operation of a mobile body. [Solution] The autonomous navigation control system for controlling the autonomous navigation of a moving object comprises: an intent information transmission unit that generates intent information including the moving object's course information and speed information and transmits it periodically; a transmission period setting unit that sets a variable transmission period for the intent information according to the collision risk of the moving object; and a behavior determination unit that determines whether the predicted behavior of the moving object matches the actual behavior of the moving object. If the behavior determination unit determines that the predicted behavior and the actual behavior do not match, the intent information transmission unit updates the intent information based on the actual behavior and transmits it regardless of the transmission period.

Description

Technical Field

[0001] The present invention relates to an autonomous navigation control system, an autonomous navigation control method, an autonomous navigation control program, a moving body, and a server.

Background Art

[0002] In recent years, it has been known to use a moving body that autonomously navigates without a crew, such as an autonomous surface vehicle (ASV) or an unmanned surface vehicle (USV), to monitor underwater targets such as submarines or to conduct ocean observations such as crustal movements on the seabed. In the autonomous navigation of a moving body, the route is controlled while estimating the relative relationship with surrounding targets such as ships or obstacles navigating in the vicinity. For example, in Patent Document 1, in order to accurately determine the position of an object, first measurement data obtained by measuring the object from a first position by at least one moving body in a group of moving bodies, and the moving body or another moving body It has been proposed to determine the position information of the object based on the second measurement data obtained by measuring the object from the second position.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When performing navigation control while estimating the relative relationship with surrounding targets, it is possible to reduce the uncertainty of future behavior by sharing not only the current state of surrounding targets but also future navigation intentions. However, when the communication volume between the moving body and surrounding targets increases, the communication bandwidth becomes tight, the quality of the network such as an increase in delay and a decrease in throughput deteriorates, and the power consumption of the moving body also increases. As a result, the continuity of the operation of the moving body such as monitoring, observation, or navigation control may be impaired.

[0005] The present invention aims to provide an autonomous navigation control system, an autonomous navigation control method, an autonomous navigation control program, a mobile body, and a server that can suppress a decrease in the continuity of operation of a mobile body. [Means for solving the problem]

[0006] The autonomous navigation control system of the present invention is an autonomous navigation control system for controlling the autonomous navigation of a moving object, comprising: an intent information transmission unit that generates intent information including the heading information and speed information of the moving object and transmits it periodically; a transmission period setting unit that sets a variable transmission period for the intent information according to the collision risk of the moving object; and a behavior determination unit that determines whether the predicted behavior of the moving object matches the actual behavior of the moving object. The transmission cycle setting unit shortens the transmission cycle as the collision risk increases and extends the transmission cycle as the collision risk decreases. If the behavior determination unit determines that the predicted behavior and the actual behavior do not match, the intent information transmission unit will update the intent information based on the actual behavior and transmit it, regardless of the transmission cycle.

[0007] The present invention provides an autonomous navigation control method for controlling the autonomous navigation of a moving object, comprising the steps of: generating intention information including the moving object's heading information and speed information, and periodically transmitting it; and setting the transmission period of the intention information to be variable according to the collision risk of the moving object. The steps involve shortening the transmission period as the collision risk increases and extending the transmission period as the collision risk decreases. The method includes the steps of determining whether the predicted behavior of the moving object matches the actual behavior of the moving object, and, if it is determined that the predicted behavior and the actual behavior do not match, updating the intent information based on the actual behavior and transmitting it regardless of the transmission cycle.

[0008] The autonomous navigation control program of the present invention is a program that causes a processor to execute an autonomous navigation control method.

[0009] The present invention provides a mobile body that performs autonomous navigation, comprising: an intention information transmission unit that generates intention information including the mobile body's course information and speed information and transmits it periodically; a transmission period setting unit that sets a variable transmission period for the intention information according to the collision risk of the mobile body; and a behavior determination unit that determines whether the predicted behavior of the mobile body matches the actual behavior of the mobile body. The transmission cycle setting unit shortens the transmission cycle as the collision risk increases and extends the transmission cycle as the collision risk decreases. If the behavior determination unit determines that the predicted behavior and the actual behavior do not match, the intent information transmission unit will update the intent information based on the actual behavior and transmit it, regardless of the transmission cycle.

[0010] The server of the present invention is a server for controlling the autonomous navigation of a mobile object, comprising: an intent information transmission unit that generates intent information including the mobile object's heading information and speed information and periodically transmits it from the mobile object; a transmission period setting unit that sets a variable transmission period for the intent information according to the collision risk of the mobile object; and a behavior determination unit that determines whether the predicted behavior of the mobile object matches the actual behavior of the mobile object. The transmission cycle setting unit shortens the transmission cycle as the collision risk increases and extends the transmission cycle as the collision risk decreases. If the behavior determination unit determines that the predicted behavior and the actual behavior do not match, the intent information transmission unit will update the intent information based on the actual behavior and transmit it, regardless of the transmission cycle. [Effects of the Invention]

[0011] According to the autonomous navigation control system, autonomous navigation control method, autonomous navigation control program, mobile body, and server of the present invention, by setting the transmission period of intent information variably according to the collision risk of the mobile body, the communication bandwidth can be used efficiently and a decrease in the continuity of the mobile body's operation can be suppressed. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of the autonomous navigation control system according to Embodiment 1. [Figure 2] This is a block diagram showing the schematic configuration of the mobile body 1 according to Embodiment 1. [Figure 3] This is a functional block diagram relating to local control and collision avoidance control of the mobile body 1 in Embodiment 1. [Figure 4] This is a flowchart showing the flow of autonomous navigation control in Embodiment 1. [Figure 5] This is a functional block diagram relating to local control and collision avoidance control of the mobile body 1 in Embodiment 2. [Figure 6] This is a schematic diagram of the autonomous navigation control system according to Embodiment 3. [Modes for carrying out the invention]

[0013] Embodiment 1. Figure 1 is a schematic diagram of the autonomous navigation control system according to Embodiment 1. The autonomous navigation control system of this embodiment is a system for controlling the autonomous navigation of multiple mobile bodies 1 navigating the sea. Autonomous navigation means moving while recognizing the surrounding situation and determining a course on its own, without relying on human operation or sequential instructions from an external source. In the autonomous navigation control system of this embodiment, satellite communication, which communicates between a ground control station 200 and a mobile body 1, or between multiple mobile bodies 1, via a communication satellite 300, and short-range communication, which communicates between multiple mobile bodies 1 or between a mobile body 1 and surrounding vessels OB, are combined to send and receive information regarding the status of the mobile bodies 1 and their navigation plans, and the autonomous navigation of the mobile bodies 1 is controlled based on the received information. Alternatively, in addition to satellite communication and short-range communication, the autonomous navigation control system may also use cellular communication such as LTE or 5G to send and receive information.

[0014] Mobile Vehicle 1 is a small autonomous vessel (ASV or USV) that navigates the sea surface to monitor the navigation of underwater targets such as submarines or to observe the marine environment. Specifically, Mobile Vehicle 1 detects and locates underwater sound sources such as submarines, observes marine environmental parameters such as seawater temperature, salinity, and current direction and velocity, and acquires input data for sea condition and sound field simulations based on this data. Mobile Vehicle 1 is not limited to autonomous vessels, but may also be an autonomous submarine or an unmanned aerial vehicle that flies autonomously over the sea.

[0015] The mobile body 1 is designed to satisfy the operating environmental conditions required for a ship sailing on the sea. For example, the mobile body 1 has waterproof performance to prevent seawater from entering internal electronic devices and anti-salt performance to prevent corrosion and salt damage in a seawater environment, and is designed assuming that the devices will not be damaged even under severe sea conditions.

[0016] The mobile body 1 is, for example, a so-called foil boat that moves on water with the hull floating above the water surface. By making the mobile body 1 a foil boat, the hull's immersion resistance can be reduced, enabling energy-saving high-speed and long-distance navigation. The overall length of the mobile body 1 is less than 3.0 m, for example, satisfying the inspection exemption conditions for "remotely controlled small ships" under the Ship Safety Act, and the mass of the hull, excluding the sensor unit 15 and battery 142 described later, is a mass that can be hoisted and stored by manpower or a simple crane.

[0017] The hull of the mobile body 1 has impact resistance, abrasion resistance, and seawater resistance. For example, the hull of the mobile body 1 is formed by a foamed core material polyurea resin spraying method in which polyurea resin is sprayed and coated on the outer surface of a core material made of foamed plastic. Thereby, compared with general FRP (fiber reinforced plastic) molding, it does not require press equipment or large molds, has excellent mass productivity, and can reduce manufacturing costs.

[0018] FIG. 2 is a block diagram showing the schematic configuration of the mobile body 1 according to Embodiment 1. As shown in FIG. 2, the mobile body 1 includes a processor 11, a memory 12, a communication interface 13, a power supply unit 14, a sensor unit 15, and a propulsion unit 16. The processor 11, the memory 12, the communication interface 13, the power supply unit 14, the sensor unit 15, and the propulsion unit 16 are electrically connected to each other via control lines, data lines, power supply lines, and the like.

[0019] The processor 11 functions as a control unit that controls each component of the mobile body 1 based on the processing program stored in the memory 12. The processor 11 performs autonomous navigation control of the mobile body 1 based on the processing program stored in the memory 12. The autonomous navigation control of the mobile body 1 will be described in detail later. The processor 11 is mainly composed of one or more CPUs, but a GPU, ASIC, FPGA, etc. may be combined as appropriate.

[0020] Memory 12 consists of RAM, ROM, non-volatile memory, HDD, or SSD, and functions as a storage unit that stores information necessary for controlling the mobile body 1 and information observed by the mobile body 1. Memory 12 stores instruction commands for various controls of the mobile body 1 as processing programs. Specifically, Memory 12 stores various programs, including an autonomous navigation control program for the processor 11 to execute autonomous navigation control. In addition to the programs, Memory 12 also stores various information, including parameters such as thresholds used in the execution of the programs. Note that this information does not need to be constantly stored in Memory 12, and may be stored in a storage device on the cloud or in a storage device provided at the control station 200.

[0021] The communication interface 13 functions as a communication unit for sending and receiving various information with the surrounding mobile unit 1, ship OB, control station 200, and communication satellite 300. The communication interface 13 also functions as an information acquisition unit for acquiring information necessary for the autonomous navigation control of the mobile unit 1. The communication interface 13 includes an antenna, transmitter, and receiver for satellite communication and short-range communication. For satellite communication, for example, Starlink®, a broadband communication service using a low-Earth orbit satellite constellation, is used. Using Starlink enables the transmission of large amounts of data even in high-latency or high-loss environments. Furthermore, by using Iridium SBD (Short Burst Data) or similar as a backup for satellite communication, communication is possible even when Starlink is unavailable. The satellite communication method is not limited to the above; communication via OneWeb or Kuiper may also be used.

[0022] For short-distance communication, for example, Private LoRa communication using the 920MHz band can be used. LoRa communication has excellent jamming and interference resistance due to its spread-band scheme, and its resistance to radio interference can be further enhanced by using frequency hopping and multi-channel operation in combination. Alternatively, VHF (Very High Frequency) wireless communication or UHF (Ultra High Frequency) wireless communication may be used for short-distance communication.

[0023] Furthermore, the communication interface 13 includes a GNSS (Global Navigation Satellite System) receiver that receives information from GPS (Global Positioning System) or the high-precision positioning service (MADOCA) provided by the Quasi-Zenith Satellite System "Michibiki". The GNSS receiver is, for example, a low-power FPGA control board or a USB dongle. Based on the GNSS signal received by the GNSS receiver, the position information of the mobile object 1 is acquired. As a countermeasure against GNSS signal spoofing, the GNSS receiver has a function to detect spoofing by mutually monitoring the L5 signal and the high-precision positioning service with the inertial navigation results. When spoofing is detected by the GNSS receiver, the processor 11 implements countermeasures such as switching to control that does not depend on the GNSS signal. In addition to positioning using GNSS signals, the processor 11 may also improve positioning accuracy during drift by adjusting the drift speed and direction by controlling the sea anchor effect by adjusting the depth of suspended sensors such as ADCP, which will be described later.

[0024] The power supply unit 14 functions as a power supply unit that supplies power to each component of the mobile body 1. The power supply unit 14 includes a solar panel 141 and a battery 142. The solar panel 141 is positioned on the upper surface of the hull of the mobile body 1. The solar panel 141 is a flexible elastomer-encapsulated solar cell module that has long-term durability and high water resistance, and is used, for example, in marine buoy applications. The electricity generated by the solar panel 141 is stored in the battery 142, and the electricity stored in the battery 142 is supplied to each component of the mobile body 1. The battery 142 is a rechargeable secondary battery, such as a lithium-ion battery.

[0025] The sensor unit 15 functions as an information acquisition unit that acquires information necessary for monitoring or ocean observation by the mobile body 1, as well as for autonomous navigation control. The sensor unit 15 includes at least one of the following: an acoustic sensor 151, an ocean observation sensor 152, a state sensor 153, and an electromagnetic wave sensor 154. The acoustic sensor 151 is a sensor that uses sound waves to measure the distance and direction to a target, as well as the underwater environment. The acoustic sensor 151 is, for example, a passive sonar or active sonar equipped with a hydrophone that targets a frequency band of several Hz to 20 kHz. The acoustic sensor 151 may further include a dipping sonar suspended from the hull.

[0026] The ocean observation sensor 152 is a sensor that measures ocean conditions (water temperature, salinity, density, current, etc.). Examples of ocean observation sensors 152 include CTD (Conductivity Temperature Depth Profiler) sensors and ADCP (Acoustic Doppler Current Profiler) sensors.

[0027] The state sensor 153 is a sensor that measures the state of the moving object 1, such as its attitude or movement. The state sensor 153 is an IMU (Inertial Measurement Unit) equipped with a 6-axis sensor or a 9-axis sensor consisting of, for example, an accelerometer, a gyroscope, and a magnetometer. It is also possible to estimate the waves on the sea (wave height, wave direction, and period) using the acceleration and angular velocity data of the moving object 1 measured by the state sensor 153.

[0028] The electromagnetic wave sensor 154 is a sensor that uses electromagnetic waves such as light, infrared rays, and radio waves to detect targets and measure distances. The electromagnetic wave sensor 154 includes, for example, at least one of a visible light camera, an infrared camera, a radar, and LiDAR (Light Detection and Ranging). The sensor unit 15 may also include sensors other than those mentioned above. For example, the sensor unit 15 may include various sensors to realize the functions of the mobile body 1, such as a wind direction and wind speed sensor, a pressure sensor, or a temperature sensor.

[0029] The propulsion unit 16 functions as a propulsion unit that moves the mobile body 1 forward, backward, and turns. The propulsion unit 16 includes hydrofoils 161 and thrusters 162. The hydrofoils 161 are supported by support members attached to the lower part of the hull of the mobile body 1. The propulsion unit 16 includes a plurality of hydrofoils 161. For example, the propulsion unit 16 includes two hydrofoils 161 arranged side by side in the left-right direction (short direction) near the center of the longitudinal direction of the hull, and a hydrofoil 161 located at the rear of the hull.

[0030] The thruster 162 is, for example, an electrically powered thruster having a motor and a propeller attached to the motor's rotating shaft. The thrusters 162 are provided, for example, on the underside of the hydrofoils 161 which are arranged side by side in the left-right direction. The processor 11 controls the power supplied to the motor, thereby changing the rotational speed of the propeller and thus the thrust force. Furthermore, by creating an output difference (thrust force difference) between the thrusters 162 provided on the left and right hydrofoils 161, the course of the mobile body 1 can be changed.

[0031] Next, the autonomous navigation control of the mobile body 1 in the autonomous navigation control system will be described. In this embodiment, autonomous navigation control is performed by the processor 11 of the mobile body 1. The processor 11 of the mobile body 1 controls the autonomous navigation of the mobile body 1 by combining global control, local control, and collision avoidance control based on the surrounding information acquired by the information acquisition unit. The surrounding information includes intention information of other mobile bodies 1 and AIS information from other vessels OB received via the communication interface 13, as well as information on surrounding targets and the surrounding environment such as the distance to surrounding targets, movement, and ocean conditions such as waves measured by the sensor unit 15, GNSS signals received via the communication interface 13, and information on the state of the mobile body 1 such as the attitude and movement of the mobile body 1 measured by the sensor unit 15.

[0032] AIS information is transmitted from the AIS (Automatic Identification System) installed on a ship's OB (Ownership). AIS is a device that automatically transmits information about its own vessel to surrounding vessels and receives information about other vessels. By sharing information using AIS, collision prevention, ship monitoring, and rescue operations in the event of an accident can be carried out. AIS information includes basic data such as the type, size, and identification information of the vessel, as well as status information such as current position, course, and speed, and the voyage schedule. Furthermore, VDES (VHF Data Exchange System) is being considered as a successor standard to AIS. The intent information transmitted / received by Mobile Unit 1 plays essentially the same role as AIS information and VDES information, and details will be described later.

[0033] Global control is a control method that determines the general route from the point of origin to the destination. In global control, the processor 11 determines the shortest time route or the route with the least fuel consumption based on wind, wave, ocean current, and tidal current data obtained from coastal wave models (CWM) and hybrid coordinate ocean models (HYCOM) provided by the Japan Meteorological Agency, for a target waypoint sequence from the point of origin to the destination. At this time, the processor 11 may perform an optimal route calculation using forecast data such as ocean currents, tidal currents, wind, and waves as an energy management measure. Specifically, the processor 11 may determine a route that minimizes power consumption while calculating the area that can be reached within a predetermined time using methods such as the isotemporal curve method. Furthermore, the processor 11 may perform control to suppress battery 142 consumption by maximizing the unpowered navigation time with the propeller 162 stopped, based on drift prediction simulations that actively utilize natural drift due to tidal currents and wind.

[0034] Local control is a control system that adjusts the route determined by global control according to the current surrounding conditions and the status of the equipment itself. Local control includes formation control and obstacle avoidance control for multiple mobile units. Collision avoidance control is a control system that estimates the risk of collision from the relative position and speed with surrounding targets and automatically avoids collisions if the risk of collision is high.

[0035] Figure 3 is a functional block diagram relating to local control and collision avoidance control of the mobile body 1 in Embodiment 1. As shown in Figure 3, the processor 11 has the following functional units for performing local control and collision avoidance control: a situation estimation unit 111, a plan generation unit 112, a navigation control unit 113, an intention information transmission unit 114, a collision risk estimation unit 115, a transmission cycle setting unit 116, and a behavior determination unit 117. Each functional unit is realized either by the processor 11 executing a program stored in the memory 12, or by a processing circuit such as an ASIC or FPGA.

[0036] The situation estimation unit 111 estimates the surrounding conditions of the mobile body 1 based on surrounding information acquired by the communication interface 13 and the sensor unit 15, which function as information acquisition units. The surrounding information includes GNSS signals received via the communication interface 13, intent information of other mobile bodies 1, AIS information from other vessels OB, distance to surrounding targets measured by the sensor unit 15, ocean conditions such as waves, and the attitude and movement of the mobile body 1. The surrounding conditions include the presence or absence of surrounding targets around the mobile body 1, the position of surrounding targets, and the state of surrounding targets (course, speed). Surrounding targets include mobile bodies 1 other than the mobile body 1, vessels OB, or obstacles. The surrounding conditions estimated by the situation estimation unit 111 are output to the plan generation unit 112 and the collision risk estimation unit 115.

[0037] The plan generation unit 112 generates a navigation plan based on the surrounding conditions estimated by the situation estimation unit 111. Based on the surrounding conditions and safety isolation margin estimated by the situation estimation unit 111, the plan generation unit 112 optimizes candidate trajectories (time-series data of heading and speed) under objectives (waypoint tracking and formation maintenance) and constraints (disturbances and energy management) to generate a navigation plan. The navigation plan includes heading information and speed information. The heading information includes heading, direction of heading change, and amount of heading change, and the speed information includes speed command.

[0038] As an example, the plan generation unit 112 applies a group control algorithm inspired by biological adaptation mechanisms to generate a route plan that maintains formation while adjusting distance and direction within a range where multiple mobile bodies 1 do not interfere with each other. The navigation plan generated by the plan generation unit 112 is output to the navigation control unit 113 and the intention information transmission unit 114.

[0039] The navigation control unit 113 controls the propulsion unit 16 based on the navigation plan generated by the plan generation unit 112. Specifically, the navigation control unit 113 controls the heading and speed of the mobile body 1 by individually controlling the output of the thrusters 162. For example, the navigation control unit 113 controls the output difference between the left and right thrusters 162 of the propulsion unit 16 so that the heading of the mobile body 1 satisfies the heading information in the navigation plan, and controls the output of the thrusters 162 so that the speed of the mobile body 1 satisfies the speed command in the navigation plan.

[0040] The intention information transmission unit 114 generates intention information, including course information and speed information, and transmits it periodically. The intention information is generated based on the navigation plan generated by the plan generation unit 112. The intention information is equivalent to AIS information and VDES information, and the intention information transmission unit 114 functions as AIS and VDES. In addition to course information and speed information, the intention information may include at least one of the following: basic data of the mobile body 1 (identification number, type, size, etc.), current position (latitude, longitude), navigation schedule, transmission time (timestamp), predicted horizon, application start time, and expiration date. If the intention information includes the transmission time, predicted horizon, and application start time, the recipient of the intention information (e.g., the status estimation unit 111 of another mobile body 1) can identify when the intention information was generated and when it will be applied. Furthermore, if the intent information includes an expiration date, the receiving side (for example, the status estimation unit 111 of another mobile body 1) can determine whether the intent information has expired, and if it has, it can invalidate the intent information and perform conservative avoidance.

[0041] Furthermore, the intent information transmission unit 114 may include a predicted trajectory (position sequence) or waypoint sequence for the future t seconds as course information and speed information. The predicted trajectory may be based on equal-time sampling, and may also be a feasible trajectory that includes curvature and acceleration limitations.

[0042] The collision risk estimation unit 115 estimates the collision risk based on the surrounding conditions estimated by the situation estimation unit 111. Specifically, the collision risk estimation unit 115 calculates at least one of the Closest Point of Approach (CPA) and Time to CPA (TCPA) as collision risk, based on, for example, the relative position of the moving body 1 and the surrounding target, the course and speed of the moving body 1 and the surrounding target. The Closest Point of Approach (CPA) is the distance that is predicted to be the closest approach in the future, assuming that the relative motion with respect to the surrounding target is linear motion with constant course and speed. The Time to CPA (TCPA) is the remaining time until the closest approach to the surrounding target. The collision risk estimated by the collision risk estimation unit 115 is output to the transmission cycle setting unit 116 and the navigation control unit 113. If the collision risk is above a preset threshold, the navigation control unit 113 controls the propulsion unit 16 to take evasive action. This performs collision avoidance control.

[0043] The collision risk estimation unit 115 may calculate the collision risk by weighting relative bearing, relative speed, and estimated maneuverability of the other vessel, in addition to CPA and TCPA. For example, the collision risk estimation unit 115 assigns a larger weight (e.g., 60% of the total) to CPA or TCPA. The collision risk estimation unit 115 sets the weight of relative bearing (head-on, crossing, etc.) to about 20%, making the weight of a head-on approach heavier and the weight of a rear approach lighter. The collision risk estimation unit 115 also sets the weight of relative speed to about 10%, and the weight of the other vessel's maneuverability (immobile in shallow water, large and difficult to turn, etc.) to about 10-20%, which may be increased or decreased depending on the situation. Finally, the collision risk estimation unit 115 normalizes the weights so that the sum is 1, and fine-tunes with actual sea area operational data to calculate the collision risk. This makes it possible to calculate a collision risk that is more in line with the surrounding conditions.

[0044] The transmission cycle setting unit 116 variably sets the transmission cycle of intent information according to the collision risk estimated by the collision risk estimation unit 115. As an example, a standard transmission cycle is pre-set when the collision risk, CPA or TCPA, is within a standard value (or standard range). If the CPA or TCPA estimated by the collision risk estimation unit 115 is less than the standard value, i.e., CPA or TCPA is shorter than the standard value and the collision risk is high, the transmission cycle setting unit 116 sets the transmission cycle to be shorter than the standard transmission cycle. Here, the transmission cycle setting unit 116 sets the transmission cycle so that the higher the collision risk, the shorter the transmission cycle becomes. As a specific example, if the standard value of TCPA is 120 seconds and the standard transmission cycle is 30 seconds, the transmission cycle setting unit 116 shortens the transmission cycle by 5 seconds from the standard transmission cycle to 25 seconds if the TCPA estimated by the collision risk estimation unit 115 is 100 seconds. Furthermore, if the TCPA estimated by the collision risk estimation unit 115 is 60 seconds, the transmission period setting unit 116 shortens the transmission period by 15 seconds from the reference transmission period to 15 seconds.

[0045] Furthermore, the transmission period setting unit 116 sets the transmission period to be longer than the standard transmission period if the CPA or TCPA estimated by the collision risk estimation unit 115 is greater than the standard value, that is, if the CPA or TCPA is longer than the standard value and the risk of collision is low. Here, the transmission period setting unit 116 sets the transmission period so that the lower the risk of collision, the longer the transmission period becomes. As a specific example, if the standard value of TCPA is 120 seconds and the standard transmission period is 30 seconds, the transmission period setting unit 116 will extend the transmission period by 15 seconds from the standard transmission period to 45 seconds if the TCPA estimated by the collision risk estimation unit 115 is 240 seconds. Also, the transmission period setting unit 116 will extend the transmission period by 30 seconds from the standard transmission period to 60 seconds if the TCPA estimated by the collision risk estimation unit 115 is 600 seconds.

[0046] Furthermore, the transmission cycle setting unit 116 may correct the transmission cycle based on a communication resource indicator that includes at least one of the communication throughput, transmission queue length, or number of transmission failures of the mobile device 1. Communication throughput is the amount of effective data that can actually be transmitted and received per certain period of time (e.g., kbps, Mbps), and it increases or decreases due to line congestion or radio wave conditions. Transmission queue length is the amount of untransmitted data (number of packets or bytes) accumulating in the transmission waiting buffer of the communication interface 13 or processor 11, and the longer it is, the more it indicates increased delay, congestion, and insufficient bandwidth. As an example, the transmission cycle setting unit 116 suppresses shortening of the transmission cycle by setting a lower limit of the transmission cycle when the communication throughput is below a preset threshold, when the transmission queue length is above a preset threshold, or when the number of transmission failures is above a preset threshold. If the transmission cycle setting unit 116 suppresses shortening of the transmission cycle, the intention information transmission unit 114 may reduce the amount of intention information to be transmitted to ensure an effective delivery rate. This makes it possible to reliably transmit intention information even in environments with limited communication bandwidth.

[0047] The behavior determination unit 117 determines whether the predicted behavior of the mobile body 1 based on the navigation plan or intention information matches the actual behavior of the mobile body 1. The behavior determination unit 117 predicts the behavior of the mobile body 1 based on the navigation plan or intention information. The predicted behavior is obtained using a known ship motion model based on the navigation plan or intention information. In this case, external disturbances or response delays measured by the sensor unit 15 are taken into account, and discrepancies may occur between the predicted behavior and the navigation plan or intention information due to deviations in the course over the ground due to currents, delays in speed tracking due to acceleration / deceleration restrictions, and relaxation of the turning amount due to formation constraints. The behavior determination unit 117 also acquires the behavior of the mobile body 1 based on the GNSS signal and the measurement results of the state sensor 153 of the sensor unit 15. In this disclosure, the behavior of the mobile body 1 predicted based on the navigation plan or intention information is referred to as "predicted behavior," and the behavior of the mobile body 1 acquired based on the GNSS signal and the measurement results of the sensor unit 15 is referred to as "actual behavior." The behavior of the moving object 1 is defined as its position, course, and speed.

[0048] The behavior determination unit 117 determines that the predicted behavior and the actual behavior are inconsistent if the predicted behavior's course or speed differs from the actual behavior's course or speed, or if the difference between the predicted behavior's course or speed and the actual behavior's course or speed exceeds a preset threshold. Alternatively, the behavior determination unit 117 determines that the predicted behavior and the actual behavior are inconsistent if the position of the moving object 1 in the predicted behavior differs from the position of the moving object 1 in the actual behavior, or if the difference (lateral deviation) between the position of the moving object 1 in the predicted behavior and the position of the moving object 1 in the actual behavior exceeds a preset threshold.

[0049] Alternatively, the behavior determination unit 117 may consider the position, course, and speed of the moving object 1 included in the navigation plan or intention information as the predicted behavior, and determine that the predicted behavior and the actual behavior are inconsistent if the course or speed included in the navigation plan or intention information differs from the course or speed in the actual behavior, or if the difference between the course or speed included in the navigation plan or intention information and the course or speed in the actual behavior exceeds a preset threshold. Furthermore, the behavior determination unit 117 may determine that the predicted behavior and the actual behavior are inconsistent if the position of the moving object 1 included in the navigation plan or intention information differs from the position of the moving object 1 in the actual behavior, or if the difference (lateral deviation) between the position of the moving object 1 included in the navigation plan or intention information and the position of the moving object 1 in the actual behavior exceeds a preset threshold. The determination result from the behavior determination unit 117 is transmitted to the intention information transmission unit 114.

[0050] In addition to periodically transmitting intention information according to the transmission cycle, the intention information transmission unit 114 also transmits intention information according to the determination result of the behavior determination unit 117. Specifically, if the behavior determination unit 117 determines that the actual behavior of the moving object 1 does not match the predicted behavior, the intention information transmission unit 114 updates the intention information to match the actual behavior and transmits it, regardless of the transmission cycle. For example, if the heading, speed, or position included in the intention information differs from the heading, speed, or position of the actual behavior, the intention information transmission unit 114 changes the heading in the intention information to match the heading, speed, or position of the actual behavior and transmits it.

[0051] Figure 4 is a flowchart showing the flow of autonomous navigation control in Embodiment 1. Figure 4 particularly shows the flow of local control and collision avoidance control in autonomous navigation control. The processing of each step in Figure 4 is realized by the processor 11 executing the autonomous navigation control program stored in memory 12. As shown in Figure 4, first the situation estimation unit 111 estimates the surrounding situation of the mobile body 1 based on the surrounding information acquired by the communication interface 13 and the sensor unit 15 (S1). Then, the plan generation unit 112 generates a navigation plan based on the surrounding situation estimated by the situation estimation unit 111 (S2).

[0052] The navigation control unit 113 controls the propulsion unit 16 based on the navigation plan generated by the plan generation unit 112, thereby controlling the navigation of the mobile body 1 (S3). Then, the intention information transmission unit 114 generates intention information based on the navigation plan (S4). In addition, the collision risk estimation unit 115 estimates the collision risk based on the surrounding conditions estimated by the situation estimation unit 111 (S5). Then, the transmission cycle setting unit 116 sets the transmission cycle of the intention information based on the collision risk estimated by the collision risk estimation unit 115 (S6).

[0053] Next, the behavior determination unit 117 estimates the predicted behavior of the mobile body 1 (S7). The behavior determination unit 117 also acquires the actual behavior of the mobile body 1 (S8). Then, the behavior determination unit 117 determines whether the predicted behavior and the actual behavior of the mobile body 1 match (S9). If the predicted behavior and the actual behavior of the mobile body 1 do not match (S9: NO), the intention information transmission unit 114 updates the intention information based on the actual behavior and transmits it (S10).

[0054] On the other hand, if the predicted behavior of the mobile body 1 matches the actual behavior (S9:YES), the intention information transmission unit 114 determines whether or not the transmission cycle has been reached (S11). The transmission cycle is the cycle set by the transmission cycle setting unit 116 in step S6. If the transmission cycle has not been reached (S11:NO), the process returns to step S1 without transmitting the intention information. If the transmission cycle has been reached (S11:YES), the intention information is transmitted by the intention information transmission unit 114 (S12), the timer for counting the transmission cycle is reset, and the process returns to step S1, and the subsequent processing is repeated.

[0055] As described above, the autonomous navigation control system of this embodiment is configured to variably set the transmission period of intent information according to the collision risk. This makes it possible to control the amount of communication according to the collision risk, thereby suppressing a decrease in network quality due to congestion of the communication bandwidth and an increase in power consumption of the mobile body 1 due to an increase in the amount of communication. As a result, it is possible to suppress a decrease in the continuity of operations of the mobile body 1, such as monitoring, observation, or navigation control.

[0056] Furthermore, if the predicted behavior and actual behavior of mobile object 1 do not match, the intention information is updated to match the actual behavior and transmitted regardless of the transmission cycle. This suppresses erroneous estimations by the receiving side even if the transmitted intention and actual behavior deviate due to disturbances or other factors.

[0057] The functions of each functional unit performed by the processor 11 are not limited to those described above. For example, the situation estimation unit 111 may calculate a collision risk index that includes at least one of CPA and TCPA, or an information freshness index based on a delay amount that includes at least one of reception delay or transmission delay, and output it as the surrounding situation.

[0058] The plan generation unit 112 may update the safety separation margin used in generating the navigation plan based on the information freshness index calculated by the situation estimation unit 111. Alternatively, the plan generation unit 112 may calculate the information age from the reception delay or transmission delay included in the information freshness index, and increase the safety separation margin as the information age increases.

[0059] The intent information transmission unit 114 may correct the generated intent information based on the information freshness index calculated by the situation estimation unit 111. In the communication interface 13, intent information is assigned a higher priority than normal state updates, and is configured to be transmitted preferentially even when the transmission queue length is long. If the intent information transmission unit 114 determines from the information freshness index that the number of transmission failures has increased, it may temporarily extend the transmission cycle and compress the intent information. Also, if the intent information transmission unit 114 determines from the information freshness index that the communication throughput has decreased, it may reduce the amount of data in the intent information, such as by reducing the number of trajectory points in the intent information, and suppress the amount of communication.

[0060] Furthermore, the intent information transmission unit 114 may transmit intent information using satellite communication if the communication bandwidth for short-distance communication is congested, based on the information freshness index. In this case, the transmission cycle is managed separately for each channel. Alternatively, if the communication bandwidth is congested, the intent information transmission unit 114 may first generate and transmit coarse intent information (classification such as turning right / decelerating), and then transmit detailed intent information when there is sufficient bandwidth.

[0061] Furthermore, if the predicted behavior and the actual behavior do not match, the behavior determination unit 117 may classify the discrepancy as minor or severe based on the magnitude of the difference between the predicted behavior and the actual behavior, and output the determination result to the intention information transmission unit 114. The intention information transmission unit 114 may update and transmit the intention information if the discrepancy is minor, or transmit warning information if the discrepancy is severe. The warning information may include, for example, information warning to invalidate the intention information, or information notifying that emergency avoidance is in progress.

[0062] Furthermore, the behavior determination unit 117 may classify the cause of the discrepancy into "disturbance," "sensor degradation," "steering limitation," etc., and output it to the intention information transmission unit 114 along with the determination result. The cause of the discrepancy can be identified, for example, based on the shape of the difference between the predicted behavior and the actual behavior. For example, if the behavior determination unit 117 observes a persistent lateral drift for a long period of time, it will determine that the cause of the discrepancy is a disturbance such as tidal current or wind. Also, if the behavior determination unit 117 observes signs such as an increase in missing data from the sensor unit 15, a sudden increase in noise, or jumps in estimation, it will determine that the cause of the discrepancy is sensor degradation. Furthermore, if the behavior determination unit 117 observes a "saturation" pattern where the turning rate is stuck at the upper limit, or acceleration or deceleration reaches the upper limit and cannot be followed, it will determine that the cause of the discrepancy is steering limitation. The behavior determination unit 117 estimates these in combination with diagnostic information (missing data rate, rudder angle, thrust limit reached, etc.) and outputs them to the intention information transmission unit 114 with tags indicating classifications such as "disturbance," "sensor degradation," and "steering restriction," along with an indication of how likely they are (confidence level). The intention information transmission unit 114 may also transmit the cause of discrepancy included in the behavior determination unit 117 as intention information. When the receiving side (for example, the situation estimation unit 111 of another moving object 1) receives the cause of discrepancy as intention information, it can make a safety judgment, such as taking evasive action according to the cause of the discrepancy.

[0063] Furthermore, the intention information transmission unit 114 may include planning accuracy or replanning frequency as intention information. Planning accuracy is a numerical representation of "how likely the predictions ahead are to be accurate," and is normalized to a scale such as 0 to 1, taking into account the judgment result of the behavior determination unit 117, the cause of discrepancy, and the reliability. As a result, the receiving side of the intention information (for example, the planning generation unit 112 of another mobile body 1) can determine that if the planning accuracy is low or the replanning frequency is high, the disturbance is strong and there is little room for maneuvering, and can increase the safety isolation margin when generating the navigation plan. Specifically, if the communication is slow and the other party's information is outdated, if the prediction is likely to be inaccurate due to disturbances (currents, waves), or if the sensors are unstable, the receiving side (for example, the planning generation unit 112 of another mobile body 1) can adjust to the safer side by adding an additional distance ΔM to the safety isolation margin when generating the navigation plan. Furthermore, the intent information transmission unit 114 may divide the future trajectory included in the intent information into "fine (high accuracy) for the near future and coarse (low accuracy) for the distant future," and assign a degree of certainty to each division.

[0064] Embodiment 2. A navigation control system according to Embodiment 2 will now be described. Figure 5 is a functional block diagram relating to local control and collision avoidance control of the mobile body 1 in Embodiment 2. Embodiment 2 differs from Embodiment 1 in that the processor 11 includes an update request unit 118 as a functional unit. The configuration of the mobile body 1 and the functions of the mobile body 1 other than those described in this embodiment are the same as in Embodiment 1.

[0065] The update request unit 118 transmits an intention information update request to other mobile bodies 1 based on at least one of the surrounding information acquired by the communication interface 13 and the sensor unit 15, and the surrounding conditions estimated by the situation estimation unit 111. For example, the update request unit 118 transmits an intention information update request when the risk of collision increases due to the sudden appearance of a new target, such as when it receives new intention information, AIS information, or VDES information, or when it detects a new sound source. The update request unit 118 also transmits an intention information update request when the movement of a surrounding target changes unexpectedly, such as when the course of a surrounding target changes abruptly, or when the CPA or TCPA with a surrounding target suddenly shortens, increasing the risk of collision. Furthermore, the update request unit 118 transmits an intention information update request when the reliability of the intention information decreases, such as when the received intention information becomes outdated, the validity period of the received intention information is exceeded, or a warning is received from another mobile body 1 belonging to the same formation.

[0066] The update requests transmitted from the update request unit 118 may be in stages. For example, the update request unit 118 may request "resend only the intent information" as a minor update request, and "detailed information including the trajectory with horizon, accuracy, and cause tag" as a major update request. When mobile unit 1 receives an update request from another mobile unit 1, it updates the intent information using the intent information transmission unit 114 and transmits it regardless of the transmission cycle.

[0067] In the navigation control system of this embodiment, intent information is normally transmitted as a push transmission according to the transmission cycle, and intent information is requested from the receiving side via a pull only when the risk of collision increases or the reliability of the information decreases. This allows for stable navigation to be continued without wasting communication bandwidth.

[0068] Embodiment 3. A navigation control system according to Embodiment 3 will now be described. Embodiment 3 differs from Embodiment 1 in that at least one of the functional units executed by the processor 11 of the mobile body 1 in Embodiment 1 is executed by a server 2 provided at a land-based control station 200. Figure 6 is a schematic configuration diagram of the navigation control system according to Embodiment 3. The control station 200 is equipped with a server 2 that manages the autonomous navigation control of multiple mobile bodies 1. The server 2 comprises a processor 21, a memory 22, a communication interface 23, and an input / output interface 24. The processor 21, memory 22, communication interface 23, and input / output interface 24 are electrically connected to each other via control lines, data lines, power lines, etc.

[0069] The processor 21 functions as a control unit that controls the components of the server 2 based on processing programs stored in the memory 22. The processor 21 performs autonomous navigation control of multiple mobile units 1 based on processing programs stored in the memory 22. The processor 21 is mainly composed of one or more CPUs, but may be combined with a GPU, ASIC, FPGA, etc. as appropriate.

[0070] Memory 22 consists of RAM, ROM, non-volatile memory, HDD, or SSD, and functions as a storage unit. Memory 22 stores instruction commands for various controls of Server 2 as processing programs. Specifically, Memory 22 stores a program for Processor 21 to execute autonomous navigation control. In addition to the program, Memory 22 also stores various information, including parameters such as thresholds used in the execution of the program. Note that this information does not need to be constantly stored in Memory 22; it may be stored in a cloud storage device connected via a wireless network.

[0071] The communication interface 23 functions as a communication unit for sending and receiving various information with the mobile body 1 and other vessels via the communication satellite 300. The communication interface 23 includes an antenna, transmitter, and receiver for satellite communication. Satellite communication technologies such as Starlink®, Iridium SBD, OneWeb, or Kuiper may be used. In addition to satellite communication, the communication interface 23 may also send and receive information using cellular communication such as 5G.

[0072] The input / output interface 24 functions as an input unit that receives user input to the server 2 and an output unit that outputs arbitrary information. The input / output interface 24 includes, for example, physical key buttons, a mouse or keyboard, and a display consisting of an LCD panel, an organic EL display or a plasma display, etc. The input / output interface 24 may also include a touch panel, a microphone that enables voice input, a camera or a scanner, etc.

[0073] The processor 21 of server 2 has, as a functional unit, at least one of the situation estimation unit 111, plan generation unit 112, intention information transmission unit 114, collision risk estimation unit 115, transmission cycle setting unit 116, behavior determination unit 117, and update request unit 118 as described in Embodiments 1 and 2. For example, the processor 21 of server 2 may have a situation estimation unit 111, receive surrounding information acquired from the mobile body 1 by the mobile body 1 information acquisition unit, estimate the surrounding situation, and transmit it to the mobile body 1. Alternatively, the processor 21 of server 2 may have a plan generation unit 112, generate a navigation plan based on the surrounding situation estimated by the mobile body 1 or server 2, and transmit it to the mobile body 1.

[0074] Furthermore, the processor 21 of server 2 may have an intention information transmission unit 114, which generates intention information including course information and speed information based on the navigation plan generated by mobile body 1 or server 2, and transmit it to mobile body 1, causing mobile body 1 to transmit it periodically. Also, the processor 21 of server 2 may have a collision risk estimation unit 115, which estimates the collision risk based on the surrounding conditions estimated by mobile body 1 or server 2. Also, the processor 21 of server 2 may have a transmission period setting unit 116, which may variably set the transmission period of intention information by mobile body 1 according to the collision risk estimated by mobile body 1 or server 2. Also, the processor 21 of server 2 may have a behavior determination unit 117, which may determine whether the predicted behavior of mobile body 1 based on the navigation plan or intention information matches the actual behavior of mobile body 1.

[0075] Furthermore, the processor 21 may superimpose the intent information of each mobile object 1 onto the relative diagram as a vector or trajectory at the input / output interface 24. If the intent information becomes outdated, the color may be changed to issue a warning. This allows air traffic controllers to easily grasp the status of multiple mobile objects 1.

[0076] In the navigation control system of this embodiment, at least a portion of the autonomous navigation control of the mobile body 1 is performed by the server 2 located in the control station 200, thereby reducing the power consumption and computing resources of the mobile body 1 and enabling stable navigation to continue.

[0077] Furthermore, the processor 11 of mobile unit 1 or the processor 21 of server 2 may be equipped with an intention alignment (conflict resolution) algorithm. Intention alignment is a mechanism that "resolves contradictions when multiple ships (mobile unit 1 and other ships) are likely to collide if they move according to their respective intentions." For example, if maintaining the formation of mobile unit 1 is prioritized, a collision with other ships may occur. Therefore, the priority of navigation control is first determined. For example, the priority may be safety > adherence to collision avoidance rules > formation maintenance > energy saving. Next, the intention information (course, speed, trajectory) of each mobile unit 1 is simulated in the future to evaluate whether constraints such as minimum distance and turning rate are met. If the constraints are not met, the degrees of freedom that can be changed (slightly reducing speed, moving towards the avoidance side, temporarily loosening the formation, etc.) are used to select a combination that does not result in a collision overall. By using the intention alignment algorithm, a "compromise that does not result in a collision and does not compromise the objectives (formation and energy saving) as much as possible" can be automatically created.

[0078] The embodiments and variations of this disclosure are presented as examples and are not intended to limit the scope of this disclosure. These embodiments and variations can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of this disclosure. These embodiments and their variations are included in the scope and spirit of the invention and in the scope of the invention and its equivalents as described in the claims.

[0079] The processes and procedures described in this disclosure can be implemented not only by those expressly described in the embodiments, but also by software, hardware, or a combination thereof. Specifically, the processes and procedures described in this disclosure can be implemented by implementing logic corresponding to the processes on media such as integrated circuits, volatile memory, non-volatile memory, magnetic disks, and optical storage. Furthermore, the processes and procedures described in this disclosure can be implemented as computer programs and executed by various computers, including processing units and servers.

[0080] Even if the processes and procedures described in this disclosure are described as being performed by a single device, software, component, or module, such processes or procedures may be performed by multiple devices, multiple software, multiple components, and / or multiple modules. Similarly, even if the various types of information described in this disclosure are described as being stored in a single memory or storage unit, such information may be distributed and stored in multiple memories on a single device or in multiple memories distributed across multiple devices. Furthermore, the software and hardware elements described in this disclosure may be implemented by integrating them into fewer components or by decomposing them into more components. [Explanation of Symbols]

[0081] 1 Mobile unit, 2 Server, 111 Situation estimation unit, 112 Plan generation unit, 113 Navigation control unit, 114 Intent information transmission unit, 115 Collision risk estimation unit, 116 Transmission cycle setting unit, 117 Behavior determination unit, 118 Update request unit, 200 Control station, 300 Communication satellite, OB Ship.

Claims

1. An autonomous navigation control system that controls the autonomous navigation of a moving object, An intention information transmission unit generates intention information including the course information and speed information of the moving object and periodically transmits it, A transmission period setting unit that sets the transmission period of the intent information to vary according to the collision risk of the moving body, A behavior determination unit that determines whether the predicted behavior of the moving body matches the actual behavior of the moving body, Equipped with, The transmission period setting unit shortens the transmission period as the collision risk increases, and extends the transmission period as the collision risk decreases. The intent information transmission unit is an autonomous navigation control system that, when the behavior determination unit determines that the predicted behavior and the actual behavior are inconsistent, updates the intent information based on the actual behavior and transmits it regardless of the transmission cycle.

2. An information acquisition unit that acquires information about the surroundings of the aforementioned moving object, A situation estimation unit that estimates the surrounding conditions of the moving object based on the surrounding information, A planning generation unit that generates a navigation plan for the moving object based on the surrounding conditions, The system further comprises a collision risk estimation unit that estimates the collision risk based on the surrounding conditions, The autonomous navigation control system according to claim 1, wherein the intention information transmission unit generates the intention information based on the navigation plan.

3. The information acquisition unit includes a sensor unit for measuring the state of the moving object. The behavior determination unit, Based on the aforementioned navigation plan or intention information, predict the predicted behavior. The actual behavior is obtained based on the measurement results of the sensor unit. The autonomous navigation control system according to claim 2, which determines that the predicted behavior and the actual behavior are inconsistent when the predicted behavior's position, course, or speed differs from the actual behavior's position, course, or speed, or when the difference between the predicted behavior's position, course, or speed and the actual behavior's position, course, or speed exceeds a preset threshold.

4. The autonomous navigation control system according to any one of claims 1 to 3, wherein the transmission cycle setting unit corrects the transmission cycle based on a communication resource indicator that includes at least one of the communication throughput of the mobile body, the transmission queue length, or the number of transmission failures.

5. If the predicted behavior and the actual behavior do not match, the behavior determination unit classifies the discrepancy as minor or severe based on the magnitude of the difference between the predicted behavior and the actual behavior. The autonomous navigation control system according to any one of claims 1 to 3, wherein the intention information transmission unit updates and transmits the intention information based on the actual behavior when the mismatch is minor, and transmits warning information when the mismatch is severe.

6. The aforementioned situation estimation unit calculates an information freshness index based on the amount of delay, which includes at least one of the reception delay or the transmission delay. The autonomous navigation control system according to claim 2 or 3, wherein the plan generation unit updates the safety separation margin used for generating the navigation plan based on the information freshness index.

7. The autonomous navigation control system according to claim 2 or 3, further comprising an update request unit that transmits an update request for intent information to a moving object other than its own device, based on at least one of the surrounding information and the surrounding conditions.

8. The autonomous navigation control system according to any one of claims 1 to 3, wherein the intent information further comprises at least one of the transmission time of the intent information, the predicted horizon, the application start time, the expiration date, the predicted future trajectory, the planning accuracy, the replanning frequency, and the cause of the discrepancy.

9. An autonomous navigation control method for controlling the autonomous navigation of a moving object, The steps include generating intention information including the course information and speed information of the moving object and transmitting it periodically, A step of setting the transmission period of the intent information to vary according to the collision risk of the moving body, wherein the higher the collision risk, the shorter the transmission period, and the lower the collision risk, the longer the transmission period, A step of determining whether the predicted behavior of the moving body matches the actual behavior of the moving body, An autonomous navigation control method comprising the step of updating the intent information based on the actual behavior and transmitting it, regardless of the transmission cycle, if it is determined that the predicted behavior and the actual behavior do not match.

10. An autonomous navigation control program for causing a processor to execute the autonomous navigation control method described in claim 9.

11. A mobile vehicle that performs autonomous navigation, An intention information transmission unit generates intention information including the course information and speed information of the moving object and periodically transmits it, A transmission period setting unit that sets the transmission period of the intent information to vary according to the collision risk of the moving body, A behavior determination unit that determines whether the predicted behavior of the moving body matches the actual behavior of the moving body, Equipped with, The transmission period setting unit shortens the transmission period as the collision risk increases, and extends the transmission period as the collision risk decreases. The intent information transmission unit, when the behavior determination unit determines that the predicted behavior and the actual behavior are inconsistent, updates the intent information based on the actual behavior and transmits it regardless of the transmission cycle.

12. A server that controls the autonomous navigation of a mobile object, An intention information transmission unit generates intention information including the course information and speed information of the moving body and transmits it periodically from the moving body, A transmission period setting unit that sets the transmission period of the intent information to vary according to the collision risk of the moving body, A behavior determination unit that determines whether the predicted behavior of the moving body matches the actual behavior of the moving body, Equipped with, The transmission period setting unit shortens the transmission period as the collision risk increases, and extends the transmission period as the collision risk decreases. The intent information transmission unit is a server that, when the behavior determination unit determines that the predicted behavior and the actual behavior do not match, updates the intent information based on the actual behavior and transmits it regardless of the transmission cycle.

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